[Qt-interest] how to resolve this moc linker error

[Matthias Pospiech]

Malyushytsky, Alex schrieb:
> I would double check that you built mentioned dll with Q_OBJECT macro defined there.
> Also it is probably worth to verify that your import / export was defined properly.
>   
I am familiar with this import/export code for msvc, but to check I post 
it now here.

QCameraImage is not specific to my project (it is used in now 2 
projects, to share the code).
That itsself is troublesome if one wants to use it in a library. 
QCameraImage.h is thus importet with svn:externals.

---- QCameraImage.h -->
#ifndef CAMERAIMAGE_H_
#define CAMERAIMAGE_H_

// IMPORTANT: You must add an QCameraImage.cpp file with such content
// #include "<Global Definitions File>.h"
// #include "QCameraImage.h"

#include <windows.h>


#ifdef QSMXCAMERA_EXPORT
    #define QCAMERAIMAGEEXPORT QSMXCAMERA_EXPORT
#else
    #ifdef QCAMERA_EXPORT
        #define QCAMERAIMAGEEXPORT QCAMERA_EXPORT
    #else
        #define QCAMERAIMAGEEXPORT
    #endif
#endif

#include <QtGui/QWidget>
...

class QCAMERAIMAGEEXPORT QCameraImage : public QWidget
{
    //Q_OBJECT
public:
    QCameraImage(QWidget* parent = 0, Qt::WFlags flags = 0)
...
<----------------------------

To make it compile I require a local QCameraImage.cpp in each project 
(which is only required for msvc)
---- QCameraImage.cpp -->
#include "QCameraSMXGlobal.h"
#include "QCameraImage.h"
<----------------------------

The QCameraWidget class itsself is very simple, here it is identical 
with QCameraImage

---- QCameraWidget.h -->
#ifndef QCAMERAWIDGET_H
#define QCAMERAWIDGET_H

#include "QCameraGlobal.h"
#include "QCameraImage.h"

class QCAMERA_EXPORT QCameraWidget : public QCameraImage
{
Q_OBJECT
public:
    explicit QCameraWidget(QWidget *parent = 0);
};

#endif // QCAMERAWIDGET_H
<----------------------------

---- QCameraWidget.cpp -->

#include "qcamerawidget.h"

QCameraWidget::QCameraWidget(QWidget *parent) :
    QCameraImage(parent)
{
}
<----------------------------

As I said, QCameraWidget is  then used in the ui of MainWindow.cpp


The Import/Export Definitions are this

---- QCameraGlobal.h -->
#ifndef QCAMERA_GLOBAL_H
#define QCAMERA_GLOBAL_H

#include <QtGlobal>
#if defined(Q_WS_WIN)

#ifdef UEYECAMERA_DLL

#if defined(UEYECAMERA_NODLL)     // Do not create a DLL library
    #define QCAMERA_EXPORT
#else
    #if defined(UEYECAMERA_MAKEDLL) // create a DLL library
        #define QCAMERA_EXPORT  __declspec(dllexport)
    #else                           // use a DLL library
        #define QCAMERA_EXPORT  __declspec(dllimport)
    #endif
#endif

#endif // UEYECAMERA_DLL

#endif // Q_WS_WIN

#ifndef QCAMERA_EXPORT
#define QCAMERA_EXPORT
#endif

#endif // QCAMERA_GLOBAL_H
<----------------------------

I think that is mainly what you were suggesting?

Matthias